The present invention relates to an apparatus for assisting a weft, picked up into a shed of any jet loom by the jetting action of compressed fluid discharged from the main nozzle into the weft picking channel, in being picked through said shed completely by means of novel auxiliary nozzles which are adapted to issue auxiliary jets of fluid into the picking channel of said loom. It relates, more specifically, to the provision of an auxiliary nozzle which has jetting apertures or outlets for weft-flight assisting and stabilizing, respectively, formed therein so that the weft being picked through the shed may be corrected properly by the streams of fluid jetted from such outlets of said auxiliary nozzle.
Auxiliary nozzles in fluid-jetting type looms call for fulfillment of two different functions; namely, (A) to assist or aid the weft in being inserted through the shed, and (B) to stabilize the weft being thus inserted through said shed. In order that the first requirement (A) is met successfully, the fluid should be discharged from the auxiliary nozzles in such a way that the fluid impinges against the weft with preferably as small angle as possible with respect to the direction of weft movement; whereas, to fulfill the second requirement (B) properly, the fluid should act on the weft being picked preferably perpendicularly thereto as much as possible. In actual picking operation in connection with the second functional requirement (B), however, there is a tendency that jetting auxiliary fluid more perpendicular to the weft will make it easier for such fluid to escape through the gaps formed between the weft guiding members, thereby allowing the weft to be entrained by such escaping fluid with a result that the weft as well would escape out of the weft picking channel formed by the guiding members.
Auxiliary nozzles heretofore, which have attempted to fulfill the aforesaid two requirements (A) and (B) by means of fluid jetted from a single outlet, pose difficulty in proper selection of effective angle and velocity at which the fluid is jetted from the auxiliary nozzles. In other words, it is required that the weft should be pushed preferably deeper into the opening of the weft guiding members for meeting the functional requirement (B), but by so doing the requirement (A) tends to become in turn more difficult to be accomplished, whereby very careful consideration must be provided to the setting of fluid jetting velocity.
To cite for your reference for better understanding of the present invention, our U.S. patent application Ser. No. 15,486 (filed on Feb. 26, 1979) is an invention which places more emphasis on fulfillment of the above-described functional requirement (B).